- "1->2"
- "1->2->3"
- "1->2->3->4"
- "5->6"
- "5->6->7"
- "5->6->7->8"

"1->2->3->4"
"5->6->7->8"

public class Program
{
    public static void Main(string[] args)
    {
        List<(string, i)> flattenedPaths = new List<(string, i)>
        {
                ("1->2", 0)
                ("1->2->3", 1)
                ("1->2->3->4", 2)
                ("5->6", 3)
                ("5->6->7", 4)
                ("5->6->7->8", 5)
        };

        IEnumerable<string> uniquePaths = GetUniquePaths(flattenedPaths);
    }

    public static IEnumerable<(string, int)> GetUniquePaths(List<(string, int)> Paths)
    {
        for (int i = 0; i < Paths.Count; i++)
        {
            bool doesMatchContain = Paths.Skip(i)
                                    .Any(x => x.Item1.Contains(Paths[i].Item1));

            if (!doesMatchContain)
                yield return Paths[i];
        }
    }
}